Heretofore, it is known that a copolymer of an organopolysiloxane with a radical-polymerizable group and a radical-polymerizable monomer is blended as a film-forming agent for use in a cosmetic. For example, Japanese Patent No. 2704730 proposes that a vinyl-based polymer obtained by copolymerizing dimethylpolysiloxane containing a radical-polymerizable group at one terminal with various types of alkyl acrylates is blended in a cosmetic. The aforementioned vinyl-based polymers provide water repellency and smoothness to a cosmetic. On the other hand, there are disadvantages in that poor miscibility with other cosmetic raw materials is exhibited since a linear silicone is grafted, and therefore, poor stability in blending in a cosmetic is exhibited, as well as a film formed therefrom fails to have sufficient sebum resistance and adhesive properties with respect to hair and skin.
In order to solve the problems described above, a cosmetic raw material containing a vinyl-based polymer having a carbosiloxane dendrimer structure, or containing both a carbosiloxane dendrimer structure and a fluorinated organic group, as a main component has been suggested (see Japanese Unexamined Patent Application, First Publication No. 2000-63225; and Japanese Unexamined Patent Application First Publication No. 2003-226611). Even in the case of using the aforementioned vinyl-based polymers, sufficiently satisfied water resistance, sebum resistance and the like cannot be exhibited, and in particular, sufficient glossiness cannot be provided on a film formed therefrom.
On the other hand, Japanese Unexamined Patent Application, First Publication No. 2000-119139 proposes a vinyl-based polymer between a dimethylpolysiloxane containing a radical-polymerizable group at one terminal and an alkyl acrylate monomer containing a long-chain alkyl group with 16 to 22 carbon atoms. The aforementioned vinyl-based copolymer is superior with respect to the copolymers described in Japanese Patent No. 2704730, but has problems such as poor sebum resistance and the like, and further improvements thereon are needed.